Since power consumption in an entire network is increased along with an increase in communication traffic, it is desirable to improve a power efficiency at the time of a communication. In view of the above, a method of determining a route when a communication is started in accordance with electric energy used for the communication is proposed. For example, plural routes are calculated as candidates when a packet transfer is conducted. One candidate among the plural routes is selected where the increase is low in the power consumption when the packet transfer is conducted. According to this method, a route calculation apparatus calculates increased amounts of power consumption in the network at a time when a path is set with regard to plural candidates of transfer routes from a starting point to a terminal point of the path to be set and determines the transfer route of the route in accordance with the calculated increased amounts.
A system is also proposed in which an increased amount of link power consumption due to a request flow is estimated, and a cost value is set on the basis of the increased amount of the link power consumption, so that a route where a total sum of the cost values is the lowest is determined as a route of the request flow. A route calculation method is further proposed in which a cost value of a route from one transfer apparatus to the other transfer apparatus is defined as a sum of power consumptions in the respective transfer apparatuses, and a route set between the transfer apparatus serving as a starting point and the transfer apparatus serving as a terminal point is determined on the basis of the cost value.
Japanese Laid-open Patent Publication No. 2008-219067, Japanese Laid-open Patent Publication No. 2011-199836, and Japanese Laid-open Patent Publication No. 2008-311830 are examples of related art.